There is only one thing one needs to know about Robert M. eyewear - Spectacles for Humans does not carry it. Draw your own conclusions.
However, I do nominate them for the "The Emperor Has No Clothes" award.

In the past couple of weeks we've received waves of phone calls and emails about "best sunglasses" on the market.
All better brands we see today have something good to offer. Some go for style, some give you function; all you have to do is pick one that suits your needs/style. If I had to single out one line that features quality lenses and still pays attention to what their frames look like, it will be Salt Optics. There are plenty of others that will work just...

Polymers, polymers, polymers!
In Americania it is called Zyl, I while the rest of the world lives comfortably with acetate of cellulose. The most important factor is whether it is mold-injected (cheap) or cut from a single sheet of material (not cheap).
Anyway you look at it, the material is incredible and is here to stay.

Prodesign is an example of a good company gone big. Some of the things they did in the early 90's were downright revolutionary and as far as design goes, they were very innovative and sharp...
I believe everything is made in China nowadays, which leads to very poor quality of finishes in titanium frames. Acetates are not affected as much, but at price point, they are everywhere you look.
In short, Prodesign is in the money making mode right now.